[openib-general] [MAD] RMPP reassembly

[Sean Hefty]

Roland Dreier wrote:

>     Sean> * In order to send RMPP ACKs, etc. the RMPP code needs
>     Sean> access to a MR (LKey actually) usable with the registered
>     Sean> mad_agent.
> 
> We discussed this once back in September of last year.  For some
> reason we decided that the consumer was responsible for managing
> memory registration, but I don't remember why.

I can't remember either, but I don't know if we thought about 
internally generated MADs sent on behalf of the user.  I will continue 
to try to find that discussion.

At a minimum, the RMPP code either needs the user to provide a MR that 
it can use when registering for the MAD service, or it needs to 
allocate one internally.  If the latter approach is used, exposing it 
to the user seems to make sense.

For QP 0/1 traffic, the RMPP layer could cheat a little and allocate a 
single MR per port, rather than per mad_agent, similar to what the CM 
and SA module do.  But then a different method would be needed if we 
ever wanted to support RMPP on a redirected QP.

- Sean